US 12,344,996 B2
Bio-based waterproof and oil-proof wrapping paper and preparation method thereof
Zhu Long, Wuxi (CN); and Ruifeng Zhu, Wuxi (CN)
Assigned to Jiangnan University, Wuxi (CN)
Filed by Jiangnan University, Wuxi (CN)
Filed on Jun. 16, 2023, as Appl. No. 18/210,709.
Claims priority of application No. 202210722909.2 (CN), filed on Jun. 21, 2022.
Prior Publication US 2023/0323602 A1, Oct. 12, 2023
Int. Cl. D21H 19/12 (2006.01); D21H 17/66 (2006.01); D21H 19/40 (2006.01); D21H 19/44 (2006.01); D21H 19/82 (2006.01); D21H 21/16 (2006.01); D21H 27/10 (2006.01)
CPC D21H 21/16 (2013.01) [D21H 17/66 (2013.01); D21H 19/12 (2013.01); D21H 19/40 (2013.01); D21H 19/44 (2013.01); D21H 19/82 (2013.01)] 13 Claims
 
1. A method for preparing a bio-based waterproof and oil-proof wrapping paper, which comprises:
(a) impregnating base paper in a calcium chloride solution to initiate pretreatment,
(b) removing the base paper from the solution, and
(c) drying the base paper to obtain a calcium chloride pretreated base paper;
(d) uniformly mixing sodium alginate, a plasticizer, and water to obtain a sodium alginate solution, wherein the sodium alginate solution comprises 0.5% to 2.0% by mass of the sodium alginate and 0.4% to 0.6% by mass of the plasticizer, and wherein the plasticizer comprises one or more of glycerol, xylitol, and sorbitol;
(e) uniformly mixing an acetic acid aqueous solution, chitosan, the plasticizer, and a crosslinking agent to obtain a chitosan solution, wherein the chitosan solution comprises 1.0% to 3.0% by mass of the chitosan, 0.4% to 0.6% by mass of the plasticizer, and 0.8% to 1.2% by mass of the crosslinking agent, and wherein the crosslinking agent comprises one or more of itaconic acid and vanillic acid;
(f) coating a surface of the calcium chloride pretreated base paper with the sodium alginate solution,
(g) drying the coated pretreated base paper from (f) to obtain a single-layer oil-proof paper;
(h) coating a surface of the single-layer oil-proof paper with the chitosan solution, and
(i) drying to obtain a double-layer oil-proof paper;
(j) preparing a biological wax-nanoparticle solution by adding nanoparticles into a biological wax solution to obtain a biological wax-nanoparticle solution;
(k) treating a surface of the double-layer oil-proof paper from (i) by coating a surface of the double-layer oil-proof paper with the biological wax-nanoparticle solution from (j), and
(l) drying the double-layer oil-proof paper from (k) to obtain a bio-based waterproof and oil-proof wrapping paper;
wherein the biological wax comprises one or more of carnauba wax, beeswax, soybean wax, and candelilla wax;
wherein the nanoparticles comprise one or more of nano silica, having a particle size of 7 nm to 40 nm and nano zinc oxide having a particle size of 80 nm;
wherein a mass concentration of the biological wax solution is 0.2% to 5.0% and a mass concentration of the nanoparticles is 0.2% to 3.0%.